Micro-electromechanical integrated circuit device with laminated actuators

Abstract

A micro-electromechanical integrated circuit includes a substrate. Drive circuitry is positioned on the substrate. The device includes a plurality of elongate actuators. Each actuator includes a fixed end portion fast with the substrate. A free end portion is spaced from the substrate. A heating circuit is connected to the drive circuitry to heat the actuator. At least a portion of the actuator is of a material having a coefficient of thermal expansion which is such that the material is capable of thermal expansion to do work. The heating circuit is positioned to generate differential thermal expansion and contraction when heated and subsequently cooled to cause reciprocal displacement of the free end portion of the actuator. Each actuator is a laminated structure having a first metal layer and a dielectric layer. The first metal layer is interposed between the dielectric layer and the substrate and defines the heating circuit.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This is a Continuation Application of U.S. application Ser. No. 10 / 943,925 filed Sep. 20, 2004 which is a Continuation Application of U.S. application Ser. No. 10 / 728,969 filed Dec. 8, 2003, now issued as U.S. Pat. No. 6,832,828, which is a continuation of U.S. application Ser. No. 09 / 835,702 filed Apr. 16, 2001, now issued as U.S. Pat. No. 6,742,873, which is a Divisional Application of U.S. application Ser. No. 09 / 807,297, filed on Aug. 13, 2001, which is a 371 of PCT / AU99 / 00894 filed on Oct. 15, 1999, the entire contents of which are herein incorporated by reference.FIELD OF THE INVENTION [0002] The present invention relates to the construction of micro-electro mechanical devices such as ink jet printers. BACKGROUND OF THE INVENTION [0003] In international patent application PCT / AU98 / 00550, the present applicant has proposed an ink jet printing device which utilizes micro-electro mechanical (MEMS) processing techniques in the constru...

AI Technical Summary

Benefits of technology

[0036] In accordance with a fifth speci of the present invention, there is provided an inkjet printhead having a series of ink ejection nozzles for the ejection of ink, each of said nozzles interconnecting a nozzle chamber with an external atmosphere, each said nozzle having a first meniscus rim around which an ink meniscus normally forms, and an extended ink flow prevention rim spaced outwardly from said first meniscus rim and substantially encircling said first meniscus rim, arranged to prevent the flow of ink across the surface of said inkjet printhead.

[0070] an ink supply unit including at least one storage chamber for holding ik for supply to said printing arrangement, said ink supply unit including a series of spaced apart baffles configured so as to reduce the acceleration of the ink within the unit as may be induced by movement of the portable printer, whilst allowing for flows of ink to the printing arrangement in response to active demand therefrom.

[0090] In accordance with an additional aspect of the eleventh aspect of the present invention, there is provided an ink supply unit for supplying a multiple color pagewidth ink supply printhead, comprising: a first elongated member containing a series of chambers for the storage of separate color inks and formed having dimensions refined to a first accuracy and having a first elongated cavity defined therein; a second elongated member including a series of wall elements and a second elongated cavity defined therein, the second elongated cavity being adapted for the insertion of a page width ink jet printhead, the wall elements mating with corresponding elements of the first elongated member to complete the formation of the series of chambers for the supply of ink to a series of slots formed in the back of the printhead when inserted in the second elongated cavity, wherein the second elongate member is formed having dimensions refined to a second accuracy which is higher then the first accuracy.

Problems solved by technology

This is because the two main contenders—thermal ink jet and piezoelectric ink jet—each have severe fundamental problems meeting the requirements of the application.

The most significant problem with thermal inkjet is power consumption.

This is approximately 100 times that required for these applications, and stems from the energy—inefficient means of drop ejection.

The high power consumption limits the nozzle packing density, as

The most significant problem with piezoelectric ink jet is size and cost.

This is not a significant problem at the current limit of around 300 nozzles per print head, but is a major impediment to the fabrication of page width print heads with 19,200 nozzles.

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